/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * MD4C.C - RSA Data Security, Inc., MD4 message-digest algorithm
 */

/*
 * Copyright (C) 1990-2, RSA Data Security, Inc. All rights reserved.
 *
 * License to copy and use this software is granted provided that it
 * is identified as the "RSA Data Security, Inc. MD4 Message-Digest
 * Algorithm" in all material mentioning or referencing this software
 * or this function.
 *
 * License is also granted to make and use derivative works provided
 * that such works are identified as "derived from the RSA Data
 * Security, Inc. MD4 Message-Digest Algorithm" in all material
 * mentioning or referencing the derived work.
 *
 * RSA Data Security, Inc. makes no representations concerning either
 * the merchantability of this software or the suitability of this
 * software for any particular purpose. It is provided "as is"
 * without express or implied warranty of any kind.
 *
 * These notices must be retained in any copies of any part of this
 * documentation and/or software.
 */

#include <sys/types.h>
#ifdef _KERNEL
#include <sys/sunddi.h>
#else
#include <strings.h>
#endif /* _KERNEL */

#if defined(__i386) || defined(__amd64)
#define	UNALIGNED_POINTERS_PERMITTED
#endif

#include <sys/md4.h>

/*
 * Constants for MD4Transform routine.
 */
#define	S11 3
#define	S12 7
#define	S13 11
#define	S14 19
#define	S21 3
#define	S22 5
#define	S23 9
#define	S24 13
#define	S31 3
#define	S32 9
#define	S33 11
#define	S34 15

static void MD4Transform(uint32_t [4], unsigned char [64]);
static void Encode(unsigned char *, uint32_t *, unsigned int);
static void Decode(uint32_t *, unsigned char *, unsigned int);

static unsigned char PADDING[64] = {
	0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};

/*
 * F, G and H are basic MD4 functions.
 */
#define	F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define	G(x, y, z) (((x) & (y)) | ((x) & (z)) | ((y) & (z)))
#define	H(x, y, z) ((x) ^ (y) ^ (z))

/*
 * ROTATE_LEFT rotates x left n bits.
 */
#define	ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))

/* FF, GG and HH are transformations for rounds 1, 2 and 3 */
/* Rotation is separate from addition to prevent recomputation */

#define	FF(a, b, c, d, x, s) { \
		(a) += F((b), (c), (d)) + (x); \
		(a) = ROTATE_LEFT((a), (s)); \
	}
#define	GG(a, b, c, d, x, s) { \
		(a) += G((b), (c), (d)) + (x) + (uint32_t)0x5a827999; \
		(a) = ROTATE_LEFT((a), (s)); \
	}
#define	HH(a, b, c, d, x, s) { \
		(a) += H((b), (c), (d)) + (x) + (uint32_t)0x6ed9eba1; \
		(a) = ROTATE_LEFT((a), (s)); \
	}

/*
 * MD4 initialization. Begins an MD4 operation, writing a new context.
 */
void
MD4Init(MD4_CTX *context)
{
	context->count[0] = context->count[1] = 0;

	/*
	 * Load magic initialization constants.
	 */
	context->state[0] = 0x67452301UL;
	context->state[1] = 0xefcdab89UL;
	context->state[2] = 0x98badcfeUL;
	context->state[3] = 0x10325476UL;
}


/*
 * MD4 block update operation. Continues an MD4 message-digest
 * operation, processing another message block, and updating the
 * context.
 */
void
MD4Update(MD4_CTX *context, const void *_RESTRICT_KYWD inptr, size_t inputLen)
{
	unsigned int i, index, partLen;
	uchar_t *input = (uchar_t *)inptr;

	/* Compute number of bytes mod 64 */
	index = (unsigned int)((context->count[0] >> 3) & 0x3F);
	/* Update number of bits */
	if ((context->count[0] += ((uint32_t)inputLen << 3))
	    < ((uint32_t)inputLen << 3))
		context->count[1]++;
	context->count[1] += ((uint32_t)inputLen >> 29);

	partLen = 64 - index;

	/*
	 * Transform as many times as possible.
	 */
	if (inputLen >= partLen) {
		bcopy(input, &context->buffer[index], partLen);
		MD4Transform(context->state, (uchar_t *)context->buffer);

		for (i = partLen; i + 63 < inputLen; i += 64) {
			MD4Transform(context->state, (uchar_t *)&input[i]);
		}

		index = 0;
	} else {
		i = 0;
	}

	/* Buffer remaining input */
	bcopy(&input[i], &context->buffer[index], inputLen - i);
}

/*
 * MD4 finalization. Ends an MD4 message-digest operation, writing the
 *	the message digest and zeroizing the context.
 */
void
MD4Final(void *digest, MD4_CTX *context)
{
	unsigned char bits[8];
	unsigned int index, padLen;

	/* Save number of bits */
	Encode(bits, context->count, 8);

	/*
	 * Pad out to 56 mod 64.
	 */
	index = (unsigned int)((context->count[0] >> 3) & 0x3f);
	padLen = (index < 56) ? (56 - index) : (120 - index);
	MD4Update(context, PADDING, padLen);

	/* Append length (before padding) */
	MD4Update(context, bits, 8);
	/* Store state in digest */
	Encode(digest, context->state, 16);

	/* zeroize sensitive information */
	bzero(context, sizeof (*context));
}

/*
 * MD4 basic transformation. Transforms state based on block.
 */
static void
MD4Transform(uint32_t state[4], unsigned char block[64])
{
	uint32_t a = state[0], b = state[1], c = state[2], d = state[3], x[16];


	Decode(x, block, 64);

	/* Round 1 */
	FF(a, b, c, d, x[ 0], S11); /* 1 */
	FF(d, a, b, c, x[ 1], S12); /* 2 */
	FF(c, d, a, b, x[ 2], S13); /* 3 */
	FF(b, c, d, a, x[ 3], S14); /* 4 */
	FF(a, b, c, d, x[ 4], S11); /* 5 */
	FF(d, a, b, c, x[ 5], S12); /* 6 */
	FF(c, d, a, b, x[ 6], S13); /* 7 */
	FF(b, c, d, a, x[ 7], S14); /* 8 */
	FF(a, b, c, d, x[ 8], S11); /* 9 */
	FF(d, a, b, c, x[ 9], S12); /* 10 */
	FF(c, d, a, b, x[10], S13); /* 11 */
	FF(b, c, d, a, x[11], S14); /* 12 */
	FF(a, b, c, d, x[12], S11); /* 13 */
	FF(d, a, b, c, x[13], S12); /* 14 */
	FF(c, d, a, b, x[14], S13); /* 15 */
	FF(b, c, d, a, x[15], S14); /* 16 */

	/* Round 2 */
	GG(a, b, c, d, x[ 0], S21); /* 17 */
	GG(d, a, b, c, x[ 4], S22); /* 18 */
	GG(c, d, a, b, x[ 8], S23); /* 19 */
	GG(b, c, d, a, x[12], S24); /* 20 */
	GG(a, b, c, d, x[ 1], S21); /* 21 */
	GG(d, a, b, c, x[ 5], S22); /* 22 */
	GG(c, d, a, b, x[ 9], S23); /* 23 */
	GG(b, c, d, a, x[13], S24); /* 24 */
	GG(a, b, c, d, x[ 2], S21); /* 25 */
	GG(d, a, b, c, x[ 6], S22); /* 26 */
	GG(c, d, a, b, x[10], S23); /* 27 */
	GG(b, c, d, a, x[14], S24); /* 28 */
	GG(a, b, c, d, x[ 3], S21); /* 29 */
	GG(d, a, b, c, x[ 7], S22); /* 30 */
	GG(c, d, a, b, x[11], S23); /* 31 */
	GG(b, c, d, a, x[15], S24); /* 32 */


	/* Round 3 */
	HH(a, b, c, d, x[ 0], S31); /* 33 */
	HH(d, a, b, c, x[ 8], S32); /* 34 */
	HH(c, d, a, b, x[ 4], S33); /* 35 */
	HH(b, c, d, a, x[12], S34); /* 36 */
	HH(a, b, c, d, x[ 2], S31); /* 37 */
	HH(d, a, b, c, x[10], S32); /* 38 */
	HH(c, d, a, b, x[ 6], S33); /* 39 */
	HH(b, c, d, a, x[14], S34); /* 40 */
	HH(a, b, c, d, x[ 1], S31); /* 41 */
	HH(d, a, b, c, x[ 9], S32); /* 42 */
	HH(c, d, a, b, x[ 5], S33); /* 43 */
	HH(b, c, d, a, x[13], S34); /* 44 */
	HH(a, b, c, d, x[ 3], S31); /* 45 */
	HH(d, a, b, c, x[11], S32); /* 46 */
	HH(c, d, a, b, x[ 7], S33); /* 47 */
	HH(b, c, d, a, x[15], S34); /* 48 */

	state[0] += a;
	state[1] += b;
	state[2] += c;
	state[3] += d;

	/* zeroize sensitive information */
	bzero(x, sizeof (*x));
}

/*
 * Encodes input (uint32_t) into output (unsigned char). Assumes len is
 * a multiple of 4.
 */
static void
Encode(unsigned char *output, uint32_t *input, unsigned int len)
{
	unsigned int i, j;

	for (i = 0, j = 0; j < len; i++, j += 4) {
#if defined(_LITTLE_ENDIAN) && defined(UNALIGNED_POINTERS_PERMITTED)
		*(uint32_t *)(void *)&output[j] = input[i];
#else
		/* endian-independent code */
		output[j] = (unsigned char)(input[i] & 0xff);
		output[j+1] = (unsigned char)((input[i] >> 8) & 0xff);
		output[j+2] = (unsigned char)((input[i] >> 16) & 0xff);
		output[j+3] = (unsigned char)((input[i] >> 24) & 0xff);
#endif	/* _LITTLE_ENDIAN && UNALIGNED_POINTERS_PERMITTED */
	}
}

/*
 * Decodes input (unsigned char) into output (uint32_t). Assumes len is
 * a multiple of 4.
 */
static void
Decode(uint32_t *output, unsigned char *input, unsigned int len)
{
	unsigned int i, j;

	for (i = 0, j = 0; j < len; i++, j += 4) {
#if defined(_LITTLE_ENDIAN) && defined(UNALIGNED_POINTERS_PERMITTED)
		output[i] = *(uint32_t *)(void *)&input[j];
#else
		/* endian-independent code */
		output[i] = ((uint32_t)input[j]) |
		    (((uint32_t)input[j+1]) << 8) |
		    (((uint32_t)input[j+2]) << 16) |
		    (((uint32_t)input[j+3]) << 24);
#endif	/* _LITTLE_ENDIAN && UNALIGNED_POINTERS_PERMITTED */
	}

}
